Transport polymerization for materials synthesis

by Lu, Zhixiang

Abstract (Summary)

Ultrathin (10 nm ~ 1 [mu]m) poly(ethyl 2-cyanoacrylate) (PECA) films were prepared on flat surfaces via vapor deposition without experiencing the liquid phase. System pressure, monomer temperature, as well as surface initiators were studied in the process of controlling the thickness and roughness of polymer films. The growth of poly(ethyl 2-cyanoacrylate) film from patterned initiating surfaces resulted in patterned polymer films. Bulk and surface modifications have been studied in this dissertation to expand the application of poly(ethyl 2-cyanoacrylate) thin films. Polymer/metal composites were prepared using supercritical carbon dioxide. It was found that platinum formed homogeneous particles in poly(ethyl 2-cyanoacrylate) films, when poly(ethyl 2-cyanoacrylate)/poly(para-xylylene) (PPX) multilayer thin films were used as substrate for the platinum deposition, particles formed continuous layer in PECA layer while Transmission electron microscopy (TEM) did not show any platinum particles in PPX layer, which enabled the preparation of alternative conducting-isolating layers. Different functionalities can be introduced to the surface of poly(ethyl 2-cyanoacrylate) films after anhydrides, isocyanates and acyl chlorides reacted with PECA film which was reduced by LiAlH4 and BH3 . X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle measurement indicated that the reaction yield was not high, but for special applications, this method may still be useful. Vapor deposition of ethyl 2-cyanoacrylate was also applied to the nano channels of anodized aluminum membrane (AAM). PECA layers with different thicknesses can be obtained on the inner wall of the nano channels by tuning vapor flow rate, temperature and vapor deposition time. PECA nanotubes were obtained after the removal of the anodized aluminum membrane. PPX/PECA coaxial nanotubes with PPX-outer shell and PECA-inner shell were prepared by using vapor deposition of ethyl 2-cyanoacrylate (ECA) on the AAM-supported PPX nanotubes. Platinum deposition has been applied in the coaxial PPX-PECA nano tubes, platinum particles can be seen by SEM and TEM in the PECA layer or on the PECA inner surface. Gold nano particles were also formed inside of the PECA nanotubes using electroless gold deposition.